The invention relates to orthopedic bone cement. More particularly, the invention relates to a ampoule and dispenser for liquid monomer to be mixed with dry polymer as a cement component.
Orthopedic bone cement generally consists of a dry polymer component and a liquid monomer component which must be mixed together thoroughly and quickly before the cement sets. The monomer component is usually packaged in a standard glass ampoule: or ampoule which must be broken to release the monomer. The monomer must be dispensed quickly and mixed with the powdered polymer so that the cement may be properly prepared for use before it sets. In addition, glass fragments must be prevented from being dispensed with the monomer.
There are various known devices for facilitating the breaking of an ampoule and the dispensing of the ampoule contents. Many of these devices are not designed specifically for the dispensing of an orthopedic cement monomer component. Furthermore, many of the devices are complex and utilize vacuum chambers and transfer ampoules or suction tubes.
U.S. Pat. No. 3,450,319 relates to a polymeric flexible breaker for fracturing the neck of a glass ampoule.
U.S. Pat. Nos. 3,544,020 and 3,720,250 show safety devices in the form of a finger protection for grasping and breaking the end of a glass ampoule.
U.S. Pat. No. 5,129,566 relates to an ampoule holder and breaker which captures the ampoule body and which has a flexible portion, such as a bellows, portion for fracturing the neck of the ampoule.
U.S. Pat. No. 6,244,487 relates to an ampoule breaker that includes that a tip that is snapped off by a polymeric cap which is snapped over the top of the ampoule and has a fulcrum ring located at the neck of the ampoule.
U.S. Pat. No. 5,423,440 relates to a cap for resealing the ampoule which includes a protective sheath for sealing the top of the ampoule.
U.S. Pat. No. 6,099,532 relates to a disposable monomer dispenser and ampoule breaker having a portion which surrounds the body of the ampoule and a portion which engages the neck of the ampoule to fracture the same. The monomer dispensing portion of the holder includes a strainer such as a fabric mesh, to prevent glass particles from exiting the holder.
European Publication No. EP 1 031 333 relates to a device for fracturing the monomer ampoule and introducing the monomer into a powdered component.
U.S. Pat. No. 5,306,277 discloses a device which is specifically designed to break an ampoule and dispense a liquid monomer component of orthopedic cement. This device includes a syringe body adapted to receive an ampoule and break the neck thereof by wedging action against a portion of the syringe.
The device of the present invention is adapted to receive and at least partially cover a glass ampoule. The device is made of a polymeric material and is preferably placed on the glass ampoule prior to shipment. The polymeric cover performs a variety of functions, one of which is to prevent the user from cutting themselves when breaking open the glass ampoule. In addition, the polymeric cover provides some impact protection for the ampoule should it be inadvertently dropped. The cover or sleeve acts to reduce the chance of breakage by absorbing some of the impact.
The cover has an opening to pour the contents of the ampoule out after the neck of the ampoule is broken. The opening may include a mesh or screen which acts as a filter for ensuring that no glass particles are poured from the broken ampoule. Alternately, the opening may remain uncovered. This would be the case where the ampoule contains a therapeutic agent which is to be dispensed by a syringe. In this case, the therapeutic agent would be withdrawn via the syringe directly from the ampoule.
It is an object of the invention to provide a safe and simple device for opening a glass ampoule and pouring the liquid contents thereof out immediately prior to mixing with a second material.
It is an additional object of the invention to provide a breaking device which can sealingly engage the outer surface of a glass ampoule body, fracture the neck of the ampoule, move the top portion away from the ampoule body and allow the liquid to be poured out of the ampoule.
It is yet an additional object of the invention to provide a simple device for safely breaking the neck of a glass ampoule containing a liquid monomer which device filters any glass fragments out of the liquid being poured from the device.
These and other objects are achieved by a cover device for fracturing the neck of a glass ampoule of the type having a body, a top and a neck joining the body to the top. The ampoule cover is preferably made of a polymeric material, such as polyethylene or ethylene vinyl acetate (EVA), and has a cylindrical recess for engaging the cylindrical outer surface of the glass ampoule or ampoule body.
The cover contains a first portion having an interior sized to sealingly engage the body of the ampoule and a second portion having a first hollow interior section sized to capture the top of the ampoule and a second interior section communicating with the neck area of the ampoule. The second section receives the fluid once the neck of the ampoule is fractured and dispenses the same through an opening therein as the assembly is tilted. The opening has a mesh filter which traps any glass particles produced when the neck of the ampoule is fractured. The first and second portions of the cover are connected by a flexible portion such as an expandable bellows portion which is held in a contracted position on the ampoule when the top and body of the ampoule are connected. When the neck is fractured, the bellows portion expands to move the broken off ampoule top away from the ampoule body. The second interior section of the cover second portion remains in fluid communication with the neck area of the ampoule after it is fractured and the bellows expands, thus allowing the liquid in the ampoule to be poured from the opening on tilting the ampoule. Other flexible or moveable connection elements such as hinge type connection may be used to connect the first and second portions as long a those connection elements move the broken head away from the neck and out of the fluid flow path.
The first cover portion has a cylindrical hollow interior to engage the cylindrical outer surface of the body of the ampoule. The cover is made from a polymeric material such as polyethylene or EVA and is sized to sealingly engage the body of the ampoule upon insertion of the ampoule into the open end of the first portion. The cover may be placed on the ampoule prior to shipment or may be assembled to the ampoule intraoperatively. Since the first portion sealingly engages the ampoule body, a vent hole is provided in the area of the bellows, preferably on an upwardly facing surface thereof adjacent the first section of the second portion which captures the top of the ampoule. This enables the fluid to be easily poured from the second section of the second portion after the neck is fractured. The outer surface of the polymeric first portion may include ribs or ridges to enhance the gripping of the ampoule/cover combination. The first section of the second portion which captures the ampoule top has an interior shape conforming to the ampoule top and also resiliently engages the ampoule top to ensure that once the neck is broken, the top remains captured within the first section. In the preferred embodiment, the first section extends around the circumference of the ampoule top for more than 1800 and has an outer surface identical in shape to the inner surface which corresponds to the shape of the top.
While the breakable glass ampoule may contain a liquid bone cement monomer, the cover of the present invention may be used with any similarly shaped breakable ampoule or ampoule containing any fluid which requires the ampoule to be broken to be dispensed.
A method for opening a breakable fluid containing ampoule is also disclosed. Again, the ampoule has a top, a body and breakable neck portion connecting the top and the body. The method includes placing the cover over the ampoule, the cover having a first portion for receiving the ampoule body and a second portion for receiving the ampoule head and a flexible portion such as an expandable portion, connecting the first and second portions. The expandable portion is placed on the ampoule in a contracted state, being held in that state when the top is originally connected to the ampoule body. A lateral force is applied to the head, against the outer surface of the first section of the second portion of the cover to break the breakable portion or neck of the ampoule such as by using a thumb with the ampoule held in the user""s hand. The ampoule top is automatically moved away from the ampoule body after the neck of the ampoule is fractured by the expansion of the expandable cover portion from its contracted state to an expanded state. The fluid in the ampoule may then be dispensed through the filter covered opening in the second section of the second cover portion.
These and other objects and advantages of the present invention will become apparent from the following description of the accompanying drawings, which disclose several embodiments of the invention. It is to be understood that the drawings are to be used for the purposes of illustration only and not as a definition of the invention.